Fifth graders explore an
unfamiliar subject while
learning plant basics.
By Lauren Pauley, Kendra Weege, and Michele Hollingsworth Koomen
ative plants are not typically the kinds of
plants that are used in elementary classroom
studies of plant biology. More commonly,
students sprout beans or investigate with fast
plants. At the time we started our plant unit (November), our school-yard garden had an abundance of native
plants that had just started seeding, including whorled
milkweed (Asclepias verticillata). We thought this would
not only be a free resource but also an opportunity to introduce students to the plants growing right under their
noses. Unfortunately, native plants are disappearing at
an alarming rate due to human activities such as urban
development, agriculture, and the introduction of invasive species. The loss of native plants and native plant
communities decreases the amount of genetic diversity
within a community and reduces the habitat for wildlife.
Studying milkweed allowed our students to develop an
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Science and Children
understanding of this native plant’s role in a biotic community as a host plant for the monarch butterfly (Danaus
plexippus); monarchs cannot survive without milkweed
because their caterpillars eat only milkweed plants. By
examining this relationship, students build an understanding of why conservation of native plants is important. There are various species of milkweed; check to see
which ones are native to your area, or choose from one of
the many other species that are linked to a species like the
monarch (see Internet Resources).
Our four-day unit for upper elementary students includes lessons on extreme plants in extreme locations, basics of plants (including roots, stem, leaves, seeds, xylem,
and phloem), exploration of plant features, and a research
study. Our unit integrates reading and writing in science.
Our preassessment revealed that our students knew very
little about native plants.
Lesson 1: Staying Alive
The main focus for the first lesson was to gauge our students’ current understandings about plants. We asked
the students to write what they already knew about
plants, plant parts, and plant functions on a modified
KWL chart. They wrote these thoughts on sticky notes,
and we added them to columns we had created on the
whiteboard. Some examples of these thoughts include
the idea that plants are living and breathing, they can be
green, and they can make fruit. The KWL chart helped
us to know that they were not familiar with the functions of the plant parts, like the xylem and the phloem.
We then introduced an article from National Geographic
Explorer called “Staying Alive” (see Internet Resources).
This article outlines some interesting facts about plants,
especially extreme plants in extreme environments. The
article included the various needs of plants such as air,
water, soil, and sunlight. The students had recently
covered the topics of main idea and detail,
so this provided an opportunity to practice
those newly learned skills. Each student was
given a magazine with the article as well as
a graphic organizer that helped them to identify main
idea and key excerpts and details from the passage
(ELA/Literacy RI.5.1; see NSTA Connection).
We started by reading the article aloud, and then
students worked at their own pace to finish the article and fill out their organizer.
After students had finished the reading and recording of the main idea and key detail, we had a
whole-group debriefing on the article. The final
task we engaged students in was to identify things
that they still wanted to know about plants. Their
questions also went up on the board in our KWL
chart.
we began a hands-on lab with the purpose of allowing
students to use their senses to observe and explore a plant
native to Minnesota, the whorled milkweed.
We first talked about the difference between native
and non-native plants. We introduced the relationship of whorled and other milkweeds to the survival of
monarch butterflies and the importance of protecting
milkweed plants. Before students explored, we introduced them to key plant vocabulary including roots,
stem, leaves, seeds, xylem, and phloem. These words
were added to our science word wall and
were also spaced throughout the
stations that we had set up in
the classroom.
Lesson 2: Botanist
Our hook for this lesson was to introduce the word botanist into
the vocabulary of our students. We asked them what
it means to be a botanist and
when they may have seen a
botanist in the past. From there
we discussed some of the questions
that students still had after reading
the article the previous day and any
new questions. Students had questions related to carnivorous plants in Minnesota and
what we might do to stop an invasive plant like
purple loosestrife. After this brief introduction,
A monarch butterfly visits a butterfly
weed (Asclepias tuberosa) flower.
Summer 2016
33
PHOTOS COURTESY OF THE AUTHORS
At each station, we provided a vocabF I GU RE 1. ulary word with its definition, a whorled
milkweed sample, rulers, hand lenses,
Microscope graphic organizer.
and a “discovery” poster with writing
utensils for the students to record their
observations. There were four discovery
posters in all, labeled roots, leaves, stem,
and seeds.
Most milkweed plants excrete a
milky white latex when the plant tissue
is cut or injured. Students should
wash their hands after they handle the milkweed plants to remove any remaining latex. Use caution
with students with known allergies to
plants or plant products. Using the dry
specimens that students handled in our
unit placed the students less at risk for
contact with the latex.
At each station, the student was first
required to write the vocabulary word
and its definition in their own personal
science notebook. After writing these
definitions, they explored the plant part
specified on the poster at their station
using as much detail as possible and including both words
covered at each station. We brought each poster to the
and pictures on the poster and in their science notebook.
front and discussed the observations and content addWe asked students to describe how each plant part felt and
ed by students. Some examples included: the seeds are
what it looked like or smelled like. We also asked them to
kept in the pods, the leaves are ½ cm wide, the leaves are
consider how that part of the plant contributed to the plant
flat, the roots need water and sun, and the leaves work
as a whole. We gave the students six minutes at each stawith the xylem. We then compared what they found
tion before they rotated to the next one.
to what they wanted to know as well as any additional
As a wrap-up for this lesson, we brought all of the
questions that they had. An interesting point that was
students back together and discussed what they disbrought up was the purpose of the seeds and their dispersal technique as an important function of
plant reproduction. The seeds of a milkweed
pod are released by explosion. The seed pod
bursts open as it matures. Inside the seed
pod, each individual seed has attached fluff,
much like that of common dandelion. Once
the seed pod bursts open, the white fluff propels the seed into the wind where it spreads.
We displayed all student-created posters
(seeds, stem, roots, xylem and phloem) in the
classroom as a reminder of good observations
and the different plant parts.
Lesson 3: Microscopes
Students examine whorled milkweed seed pods.
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Science and Children
In this lesson, we wanted students to observe
the parts of the plants using dissecting microscopes so that they could view the plant
parts in greater detail. On day 2, students had
Native Plants and Seeds, Oh My!
Tips for Growing Milkweed
Most milkweed seeds need a period of moist cold
called cold stratification before they will germinate.
Cold stratification occurs naturally with native
plants because they are in the wild where their
seeds lie on the ground or leaf litter, are buried by
animals, and are subject to frost heave.
We have successfully mimicked cold
stratification by planting milkweed or other native
seeds in pots with moistened potting soil. Place
three to five seeds in a pot with two to three inches
of potting soil. Cover seeds with potting soil. In cold
winter areas of North America you can then place
the pots outdoors in areas where they will have
some protection from the wind.
Milkweed plants are also available at garden
centers and native plant sales.
Students observe and draw milkweed roots.
used a hand lens to observe the plant parts. We hoped
cussing why their drawings are the same or different.
that in this lesson the students would observe finer deWe would also suggest displaying these in your classroom! The students are very proud of what they have done
tails of the plant parts with the use of the microscope
and the details they added—not only are they a great con(for example, the tiny hairs on the stem of the plants).
nection to science and plant parts but also beautiful and
Using a format similar to the previous lesson, we set
interesting pieces of art!
up six stations around the room, and at each station
there was a microscope with different plant part slides
placed on the stage. Students were given a graphic organizer with six bubbles and a line under each bubble
(Figure 1; see NSTA Connection). First, the students
had to write the name of the part that they were observing on the line provided, then they took turns looking
The unit concluded with a scientific inquiry of the gerthrough the microscope at the plant part in order to
mination of milkweed seeds with varied number of weeks
draw a detailed picture of what they saw
during the five minutes they had at each
station. We circulated the room to prompt
the students about what they saw and how
it compared to what they observed during
the previous station experience. We then
had the students return to the KWL chart
and write what they learned about plants
throughout all the lessons. For example,
the students learned that the phloem carried the food or sugars through the plant,
while the xylem transported the water.
Other ideas for debriefing could include
having the students discuss what they saw
and drew in small groups. These groups
could be their microscope observation
group or a different group. They would
then be able to compare and contrast what
they saw in their different drawings, dis- Asclepias verticillata in bloom in the school garden
Lesson 4: Investigations With
Native Plants
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35
in cold stratification. We begin this
lesson by reviewing the basic parts
and functions of the whorled milkweed plant. We asked the students
to think about what might affect
the germination of the seeds undergoing cold stratification. Their suggestion of time (in weeks) guided us
to develop a research question for
the class. Students worked together
with their pod groups (4–6 students per pod) to decide how many
weeks they would place their seeds
outdoors for cold stratification. We
guided the students to develop a
research question that follows the
template: How does ______ affect
________? For example: How does
the number of weeks in cold stratifi- Students created posters that demonstrate their learning.
cation affect the rate of germination?
The independent variable was the
amount of time in weeks outdoors
think might happen, scientists recognize the possibility
with the dependent variable seed germination rate. The
for many possible outcomes, and for even the youngest
same question was used by all the groups, but the amount
students, to understand that they can be biased if they
of time under the condition of cold stratification varied.
put too much stake in the “one” hypothesis that they
After deciding on our class question, we talked with the
think will be supported. In this study, there are three
students about all the possible outcomes that might arise
possible outcomes:
in the investigations. We talked about how we define the
possible outcome of an investigation as a hypothesis. As
HO: There will be no difference in germination rates
a class we constructed multiple hypotheses or multiple
H1: More milkweed seeds will germinate in cold stratioutcomes for our investigation. We emphasized the imfication that is less than four weeks
portance of including a null hypothesis, or the possibilH2: More milkweed seeds will germinate in cold stratiity that there will be no effect. While students are often
fication that is more than four weeks
taught that their hypothesis is a prediction of what they
Examining seeds
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Science and Children
Next, in groups, students developed a
plan to conduct their research investigation
(see NSTA Connection). Students planted
seeds in clean yogurt containers with holes
drilled in the bottom (by the teacher) for
drainage, being careful to place about four
inches of moist potting soil in the pot, then
add the seeds and cover with another half
inch of soil. Students then placed their pots
in a plastic tub that was placed outdoors
(away from wind) for the length of
their experiment. Make sure students wash hands after handling soil
and plants.
Students brought their milkweed containers back into the classroom after the
specified number of weeks for cold stratification. These containers were then placed
Native Plants and Seeds, Oh My!
near a window where they documented the
germination of seeds. We made connections
back to the lessons from the fall as students
identified the plant parts and the functions of
the parts of the plants as the seeds germinated
into seedlings. The emergence of the seedlings
allowed us to also talk about the full life cycle
of the native whorled milkweed plant from
seeds (fall) to seedlings (spring). In early May,
we processed the outcomes of our investigations. Students referred back to their original
research question and used their data and
evidence to decide which hypothesis was supported. Students developed a conclusion that
included their reasoning about their data and
why their hypothesis was supported.
Conclusion
We concluded our unit by completing the
KWL chart. Our assessment allowed us to
understand that students learned the function
of the parts of the plants. For example, one
student wrote in her assessment: “The xylem Students measure the length of milkweed stems.
carries water and nutrients from roots to other
parts of the plant.” Students also learned that
Schoolyard planting of these native plants shifted our
every part of the plant has an important role in the plant’s
discussion from plant biology to plant conservation and
survival and growth (“I learned that milkweed parts don’t
how we, students and teachers, could be agents of change
just use one part of the plant, they use all”).
in propagating native plants and making a difference for
In addition, and after we completed the cold stratificanative species that depend on them, like the monarch
tion of our seeds, our class data supported the hypothesis
butterfly. Planting native plants like whorled milkweed
that more milkweed seeds will germinate in cold stratificain schoolyard gardens will allow future students to learn
tion that is more than four weeks long. Once we concluded
about these plants in other classroom investigations and
and processed the results of the experiment, we allowed
within a natural habitat.
the seedlings to continue to grow through the remainder
We were pleased at how enthusiastic the students were
of our school year, placing them outside when the weather
about
our unit! In the future, we might include the flowpermitted. When the plants were about three to four inchers
of
the milkweed plant, which would allow us to talk
es tall, they were ready to plant in our schoolyard gardens.
about the reproductive parts of the plant in more detail.
And, by considering other native plants, the possibilities
are endless! ■
Lauren Pauley is a kindergarten teacher at Becker Primary School in Becker, Minnesota. Kendra Weege is a
fourth-grade teacher at Fred Ipalook Elementary School
in Barrow, Alaska. Michele Hollingsworth Koomen
([email protected]) is an associate professor of science and mathematics education at Gustavus Adolphus
College in Saint Peter, Minnesota.
Internet Resources
Whorled milkweed seed pods
Cold Stratification
www.alchemy-works.com/fall_planting.html
Summer 2016
37
Native Plants and Seeds, Oh My!
Connecting to the Next Generation Science Standards (NGSS Lead States 2013):
5-LS1 From Molecules to Organisms: Structures and Processes
www.nextgenscience.org/pe/5-ls1-1-molecules-organisms-structures-and-processes
The chart below makes one set of connections between the instruction outlined in this article and the NGSS.
Other valid connections are likely; however, space restrictions prevent us from listing all possibilities. The
materials, lessons, and activities outlined in the article are just one step toward reaching the performance
expectations listed below.
Performance Expectation
Connections to Classroom Activity
Students:
5-LS1-1. Support an argument that plants get the
materials they need for growth chiefly from air and
water.
• demonstrate their learning about the parts,
functions, and reproduction of a plant and conduct
an investigation using seeds that supports the
argument that plants get necessary materials from
air and water.
Disciplinary Core Idea
LS1.C: Organization for Matter and Energy Flow in
Organisms
• Plants acquire their material for growth from air
and water
• demonstrate their learning about the parts,
functions, and reproduction of a plant and conduct
an investigation using seeds that supports the
argument that plants get necessary materials from
air and water.
Science and Engineering Practice
Engaging in Argument From Evidence
• plan and carry out an investigation, analyze and
interpret the collected data, use claims based on
evidence to engage in argument related to the
number of weeks needed of cold stratification for
optimal seed germination.
Connecting to the Common Core State Standards (NGAC and CCSSO 2010):
ELA/Literacy
RI.5.1 Quote accurately from a text when explaining
what the text says explicitly and when drawing
inferences from the text. (5-ESS1-1)
Lady Bird Johnson Wildflower Center
www.wildflower.org/plants
Monarch Joint Venture
www.monarchjointventure.org
National Geographic Explorer: Staying Alive by Gary Miller
http://content.yudu.com/A339au/NGXPathfinOctob2014/
resources/index.htm
Native Plant Nursery Directory
www.plantnative.org/national_nursery_dir_main.htm
Reference
Koomen, M.H., R. Blair, E. Young-Isebrand, and K.S. Oberhauser.
2014. Science Professional Development with Teachers:
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Science and Children
Students will use quotes from the National Geographic
article to explain explicitly the main idea of the text
and will draw inferences from that text related to the
main idea and supporting details.
Nurturing the Scientist Within. Electronic Journal of Science
Education 18(6).
NGSS Lead States. 2013. Next Generation Science Standards: For
states, by states. Washington, DC: National Academies Press.
www.nextgenscience.org/next-generation-science-standards.
National Governors Association Center for Best Practices and
Council of Chief State School Officers (NGAC and CCSSO).
2010. Common Core State Standards. Washington, DC:
NGAC and CCSSO.
NSTA Connection
Download student data sheets at www.nsta.org/sc1607.